Packaging comprising a container associated with a lid equipped with reversible and reusable locking means

ABSTRACT

A packaging includes a container associated with a lid equipped with reversible and reusable locking element. The container includes a metallic body having a side wall whose upper border, which delimits the upper opening of the container, is finished by an upper edge; and the lid, made out of plastic material, includes a central closing panel prolonged by a peripheral border having a U reversed section, whose the bottom is equipped with a seal, the peripheral border being suitable to cap the upper edge of the container body, during the closing of the container by the lid. The lid includes, on its periphery, at least two locking legs each connected to its peripheral border via a one piece hinge whose articulation axis extends parallel or substantially parallel to the peripheral border; each locking leg includes at least a locking part suitable to cooperate with an outer circular structure.

The present invention relates to a packaging comprising a container associated with a lid equipped with locking means of reversible and reusable type; this packaging could receive all type of products, but is specifically adapted to liquid, semi-fluid or semi-pasty consistency substances, like varnishes, lacquers or paintings.

These type of products require specific packaging, specially to take their particular consistency and toxicity into account.

Packagings in question are generally constituted of a container sealed by means of a lid equipped with locking means.

In practice, this type of packaging should not be open in an impromptu or inopportune way, but it must nevertheless be able to be easily open by the final user; this packaging must also as the tight as possible to avoid the flow of its contents when it is sealed.

The applicant developed a new structure of packaging answering perfectly to these various criteria.

In accordance with the invention, the container of packaging comprises a metallic body, obtained particularly either by stamping or by cutting, welding and rolling operations of a metallic sheet, provided with a side wall whose lower border is associated with a bottom and whose upper border, which delimits the upper opening of said container, is finished by an upper edge. In addition, the lid of the packaging, made out of plastic, comprises a central closing panel prolonged by a peripheral border having a U reversed section, whose the bottom is equipped with a seal, said peripheral border being suitable to cap the upper edge of the container body during the closing of said container by the lid; moreover, this lid comprises, on its periphery, at least two locking legs (also named flap or tab) each connected to said peripheral border via a one piece hinge whose the articulation axis extends parallel or substantially parallel to said peripheral border, said locking legs each comprising at least a locking part suitable to cooperate in a removable way with an outer structure, called “complementary locking structure”, arranged at the side of the upper border of said container body, during and in particular thanks to a swivelling operation of said locking leg in a position named as “locked”, the corresponding cooperation involving, simultaneously, a bringing nearer between the peripheral border of the lid and the upper edge of the container, to obtain the crushing of the seal.

Such a packaging proves to be very easy to open and to close thanks to the use of its locking legs. These legs take part effectively in the opening and the closing operations of the packaging by the final user; in locked position, they also optimize the sealing characteristics of the packaging.

Preferably, the upper face of the locking part and the lower face of the complementary locking structure have complementary or substantially complementary surfaces in curved general shape, suitable to cooperate one with the other during the swivelling operation of the locking legs in locked position.

According to a characteristic of realization, the upper edge of the container consists in a roll, projecting towards outside, and the complementary locking structure of the container is formed by the lower part of said rolled edge.

In this case, the rolled edge comprises advantageously, successively, from the upper border of the associated side wall, at least the following parts:

an upper part in shape of a roll, having a U section, open towards the lower border of the associated side wall, suitable to be capped by the peripheral border of the lid, and

a lower part in shape of a roll whose lower surface presents a section arranged in the general shape of half-circle or half-oval, forming the complementary locking structure and suitable to cooperate with the upper face of the locking part of the lid legs.

In an alternative way, the side wall of the body of container can comprise, at side of its upper border, a moulding projecting towards the outside and whose the lower part is shaped to constitute the complementary locking structure of the container, suitable to cooperate with the locking part of the lid legs.

According to another particularly interesting structural characteristic, some at least of the locking legs comprise a one piece lengthening forming a kind of handle facilitating, for a final user, the swivelling operation of said locking legs.

In this case, the one piece lengthening of the locking legs advantageously comprises a principal part, located at side of the locking part, continued by an end part, by the intermediary of a one piece folding line. This end part comprises, on the one hand, an opening shaped to allow the passage of the fingers of a person and its gripping, in particular to allow its swivelling compared to said principal part, and on the other hand, an extension extending in direction of the peripheral border of the lid, suitable to come resting on the outside face in opposite of the side wall of the container during the swivelling operation of said end part, this particularly to form a kind of lever and so as to facilitate the swivelling of the locking leg from the locked position up to the unlocked position.

In this case, before the first opening of the packaging, the principal part and the extension forming lever of the end part of the lengthening of the locking legs are advantageously bound via connection means which are degradable in an irreversible way, for example of the pre-cut line(s) type or of the junction point(s) type, suitable to be broken during the swivelling operation of said end part compared to said principal part, this to constitute a witness of opening or tamper evident closure.

Still in this case, the one piece extension comprises, at side of its lower face, a projecting structure suitable to reinforce this extension and to constitute the leaning part for the unlocking operation.

Moreover, always in an interesting way, the folding line extends transversely over the width of the one piece lengthening of the locking legs; and the end part of said lengthening comprises:

the opening for the passage of the fingers, arranged at the side of the free external edge of said one piece lengthening, opposed to the articulation hinge of said locking leg;

a transversal wall, arranged to form a stop limiting the possibility of introduction of the fingers into said opening; and

an extension forming lever, extending in the space of the principal part, on a part of its length and in direction of the hinge of the corresponding locking leg.

The invention will be also illustrated, without being limited, by the following description of several possible embodiments, given only as examples and showed on the following figures in which:

FIG. 1 shows, in a schematic manner and in section, the upper part of a packaging according to the invention, composed of a body container and of a complementary closing lid whose one of the locking legs is represented here in an “unlocked” position;

FIG. 2 corresponds to the packaging of FIG. 1, now in closed configuration, with the locking leg of the lid represented in a “locked” position;

FIG. 3 still corresponds to the packaging of FIGS. 1 and 2, in which the locking leg is suitably moved by the final user to cause his unlocking compared to the associated container;

FIG. 4 is a partial top view and in perspective, of a possible embodiment of the closing lid according to the invention, with one of its locking legs showed in unlocked position, before the installation on the container;

FIG. 5 is a lower view, in perspective, of the closing lid according to FIG. 4;

FIGS. 6, 7 and 8 show, each one, a possible alternative embodiment of the packaging according to the invention, constituted of a particular container associated with a lid whose the structure is similar to the one showed FIGS. 1 to 3.

Packaging 1, partially illustrated in a schematic way on FIGS. 1 to 3, is composed, on the one hand, of a container 2 comprising a metallic body 3 open at its upper part, and on the other hand, of a closing lid 4 made out of plastic which is equipped on its circumference with reusable and reversible locking means, in the shape of plurality of articulated legs 5 (only one of these locking legs 5 is represented on these FIGS. 1 to 3).

The container body 3, whose only the left upper part is illustrated on the FIGS. 1 to 3 (in an enlarged view), is carried out particularly by operations of cutting, welding, and rolling of a metallic sheet (made out of steel for example) whose the thickness can be in the range of 0.15 to 0.40 mm.

This container body 3 is in general cylindrical or parallelepiped shape. It is composed of a side wall 6 whose the lower border is associated with a bottom element (not represented), for example assembled and fixed by double seaming, and whose the upper border 7, which delimits the upper opening 9, ends by a rolled edge 10 projecting towards outside and directed towards the lower edge (not represented) of the side wall 6.

The rolled edge 10 is shaped to be suitable to cooperate with the locking legs 5 of the closing lid 4, that during an operation of said locking legs 5 in locked position (as it can be seen FIG. 2).

In this circumstance, this rolled edge 10 comprises successively, from the upper border 7 of the side wall 6 associated, the following parts:

an upper rolled part 11 having a U reversed section, opened downwardly and in direction of the lower border (not represented) of the associated side wall 6,

a connection part 12, moving away gradually from the side wall 6 in opposite, and

a lower rolled part 13 having a section in general shape of half-circle or half-oval (opened upwardly), extending towards the side wall 6 in opposite and forming a complementary locking structure, in shape of a seat, suitable to cooperate with the locking legs 5 of the closing lid 4 when said locking legs 5 are operated in locked position (FIG. 2).

The closing lid 4, of which only the left part is represented in a schematic view and in section, is made out by traditional operations of moulding-injection of a thermoplastic matter usually employed.

This lid 4 comprises a central closing panel 14 (cylindrical or polygonal) delimited by a peripheral border 15 whose lower surface has a reversed U section suitable to come to cap the upper rolled part 11 of the rolled edge 10.

The bottom of this peripheral border 15 is equipped with a seal 16, suitable to be crushed between the upper part 11 of the rolled edge 10 and the peripheral border 15 of lid 4 to ensure the sealing of packaging 1 (FIG. 2). This seal 16 can be assembled, made out of PVC foam, or it can be a solid added compound or seal which is sticked or forced into the border 15. It can also be made out in a one piece with the peripheral border 15, for example of the moulded fringes type.

This lid 4 comprises also, on its circumference, the locking legs 5 above-mentioned. The number and the localisation of these locking legs 5 are function of the container shape to close and of the size of the container; in a general way, this number is comprised between two and ten.

As illustrated on FIGS. 1 to 3, each locking leg 5 comprises a body 17 connected to the peripheral border 15 via a one piece hinge 18. This hinge 18 can consist of a simple thinning of matter, or can consist of a plurality of flexible tab; its axis of articulation extends in parallel or substantially in parallel to the peripheral border 15 (in function of the circular or polygonal shape of the lid).

These locking legs 5 comprise mainly:

a locking or gripping part 19, extending from the articulated body 17, whose curved upper face is suitable to come to cooperate in a removable and reversible way with the locking complementary structure 13 of the rolled edge 10 (FIG. 2), and

a one piece lengthening 20 of said articulated body 17, forming a kind of handle facilitating, for an user, the swivelling operation of the locking leg 5 equipped, between its locked and unlocked positions.

The corresponding locking leg 5 is particularly interesting by the fact that the structure of its one piece lengthening 20 is shaped—to simplify its manual unlocking compared to the complementary locking structure 13 of container 2, and also—to form a witness of opening or tamper evident closure.

For this purpose, the lengthening 20 comprises two parts associated by a one piece hinge 22: a principal part 20 a, at the side of the locking part 19, and an end part 20 b.

This hinge 22 extends transversely compared to the longitudinal axis of the locking leg 5, and it extends also in parallel or substantially in parallel compared to the upper hinge 18.

More precisely, the end part 20 b comprises

an interior edge 23, at the side of the hinge 22, from which a one piece extension 24 extends, that in the space of the principal part 20 a and on a portion its length; this extension 24 is provided on its lower face with a projecting structure 25, and it is joined with the principal part 20 a by a one piece joining point 26, and

a free external edge 27, formed to come in opposite and at distance to the side wall 6 of the container 2 when the locking leg 5 is operated in locked position (as described in relation to FIG. 2), to form and define an opening 28 adapted for the passage or the entrance of the fingers of an user and the gripping of said end part 20 b.

In practice, as it can be seen FIG. 1, first of all, the closing of container 2 consists in bringing the closing lid 4 on its upper opening 9, in order that the upper part 11 of its upper edge 7 is capped by the peripheral complementary edge 15. For this purpose, the locking legs 5 are advantageously in an “unlocked” position, i.e. out of the space of the rolled edge 10; preferably, these legs 5 extend in the plan or substantially in the plan of the central panel 14 of the lid 4.

Then, the locking legs 5 are operated in rotation around their one piece hinge 18, that in a direction causing their bringing closer to the side wall 6 of the associated container 2 (this movement corresponds to the direction of arrow 30 of FIG. 1).

This rotational movement of the locking legs 5, in view of locking, can be implemented manually; but in an alternative way, this operation can easily be mechanized.

During this locking operation, the locking body 19 of the leg 5 comes automatically in position by clipsage under the complementary locking structure 13 of the rolled edge 10 of container 2 (FIG. 2).

It is thus obtained, simultaneously, the locking of lid 4 on container 2, and the sealing of this container 2 by the crushing of the seal 16 between the upper edge 11 of the container body 3 and the peripheral border 15 of lid 4.

In this locked position, the leg 5 comes to locate substantially parallel to the lateral wall 6 of the container body 3; the edge of the projecting structure 25 comes next to this side wall 6 and the exterior border 27 of the end part 20 b is at distance of said wall 6 to delimit the gripping opening 28.

Then, when a final user needs to reach the content of the sealed packaging 1, he just needs to operate the locking legs 5 in unlocked position, i.e. in the direction of arrow 31 of FIG. 3 (in opposite direction compared to the locking operation, corresponding to arrow 30 of FIG. 1).

For this purpose, the final user introduces one or some fingers through lower opening 28 of the locking leg 5, so as to arrange them under the end part 20 b. Then, the final user pushes or pulls on this end part 20 b (eventually simultaneously pushing the one piece lengthening 24 towards the container side wall 6), that in a suitable manner to cause its swivelling around the hinge 22 and compared to the principal part 20 a, in direction symbolized by arrow 32 of FIG. 3.

During this operation, the end part 20 b forms a kind of lever facilitating the rotation of the locking leg 5 around its one piece hinge 18, that by the resting of its projecting structure 25 on the external face on the side wall 6 of container 2 in opposite. During this operation, the final user breaks, in an irreversible way, the one piece joining point 26 (because of the spacing between the principal part 20 a and the extension 24 of the leg, and because of the weakness of said joining point 26), thus constituting the witness of opening or tamper evidence closure of the locking leg 5.

Of course, the final user can then lock and unlock as many time as he wishes the lid 4 compared to container 2, by a manual and adapted operation of the locking legs 5.

FIGS. 4 and 5 show a particularly interesting embodiment of the lid as described above in relation to FIGS. 1 to 3.

On these figures, it can be seen a lid 4 comprising a central panel 14 delimited by a peripheral border 15 equipped with the locking legs 5 (one of these legs is visible on these figures) by the intermediary each one of a one piece hinge 18.

In the same way, the represented locking leg 5 comprises a body 17 provided with a gripping part 19, extending at the side of its lower face; this body 17 is still provided with the one piece lengthening 20 forming operation handle.

It is also here found the two parts of the lengthening 20, namely a principal part 20 a, on the side of the gripping part 19, associated with an end part 20 b via a thinned matter line 22 suitable to form a hinge; this folding line 22 extends transversely, and also in parallel or substantially in parallel to the hinge 18 of the locking leg 5.

The end part 20 b comprises an interior edge 23, at the side of the hinge 22, from which the one piece extension 24 extends, that in the space of the principal part 20 a and on a portion of its length; this extension 24 is provided on its lower face with the projecting structure 25, and it is joined with the principal part 20 a by a one piece joining point 26.

The free external edge 27 of lengthening 20 is shaped to define a lower opening 28 adapted for the passage of the fingers of the final user, and the gripping of said end part 20 b.

On FIG. 5, it is still noticed that the end part 20 b comprises a transversal wall 33, extending on the side of its rear face, next to the interior edge 23. This transversal wall 33 constitutes a stop panel suitable to allow adapted positioning of the user fingers only under the end part 20 b associated. It avoids particularly the positioning of the fingers under the extension 24 or under the principal part 20 a, which would limit the efficiency of the unlocking operation. Moreover, it prevents to use a tool to unlock the leg.

FIGS. 6, 7 and 8 each show a possible alternative embodiment of packaging according to the invention.

On FIG. 6, container 2 differs from the one described above in relation to FIGS. 1 to 3, only because of the interior shift or unwedging of the upper border 7 compared to the general width of the side wall 6.

Such a structure of container 2 is obtained by swaging of its upper border 7, before rolling of the upper edge 10, or in an alternative way, by expansion of its side wall 6. Moreover, such a shape of the container body can be used particularly with all the embodiments here described.

On FIG. 7, container 2 distinguishes from the one described here-above in relation to FIGS. 1 to 3, in that it comprises an upper rolled edge 10 comprising successively, from the upper border 7 of the side wall 6 associated, the following parts:

an upper rolled part 11 shaped in general U reversed section, opened in direction of the lower edge of the associated side wall 6,

a connection part 12, extending here in parallel and at distance from the side wall 6 in opposite, and

a lower rolled part 13 in general shape of half-circle or half-oval (in form of a buckle), extending away from the side wall 6.

As described above, the lower rolled part 13 of the rolled edge 10 constitutes the complementary locking structure suitable to cooperate with the locking legs 5 of the closing lid 4.

On FIG. 8, the side wall 6 of container 2 comprises an upper rolled edge 10 in general buckle shape, whose the upper part receives directly the peripheral border 15 of lid 4.

This side wall 6 is also provided with an external moulding 35, continuous or discontinuous, for example obtained by a drawing operation, of which the lower curved part is formed to constitute the complementary locking structure 13 cooperating by clipsage with the legs 5 of lid 4 operated in locked position.

Of course, in the case of packagings corresponding to FIGS. 6 to 8 described above, the locking part 19 of legs 5 is shaped to suitably come by clipsage under the locking structure complementary 13 associated.

In all cases, locking legs 5 are shaped to make relatively difficult their unlocking without breaking the tamper evidence closing 26.

For this purpose, the length of lengthenings 20 will be reduced to the maximum in order to limit the possibilities to use the corresponding lever. Moreover, as showed on the embodiment of the FIGS. 4 and 5, the lateral borders of the locking legs 5 can be equipped with returns 36 whose free longitudinal edge, intended to come next to the outside face of the side wall 6, fits said side wall 6 in opposite, in order to limit the possibility of inserting a swinging tool.

In the same spirit, even if the FIGS. 1 to 8 show some technical solutions in which locking seats 13 are made out in a continuous manner on the whole periphery of container 2, some alternative embodiments can have seat 13 of discontinuous sections, provided and arranged only on the zones of location of the legs 5.

The packaging in conformity with the invention can be provided with one or several locking legs, associated with one or several structure playing a role of a simple hinge. 

1. Packaging comprising a container (2) associated with a lid (4) equipped with reversible and reusable locking means, characterised in that said container (2) comprises a metallic body (3), obtained particularly either by stamping or by cutting, welding and rolling operations of a metallic sheet, provided with a side wall (6) whose lower border is associated with a bottom and whose upper border (7), which delimits the upper opening (9) of said container (2), is finished by an upper edge (10), and in that said lid (4), made out of plastic material, comprises a central closing panel (14) prolonged by a peripheral border (15) having a U reversed section, whose the bottom is equipped with a seal (16), said peripheral border (15) being suitable to cap said upper edge (10) of body container (3) during the closing of said container (2) by the lid (4), said lid (4) comprising also, on its periphery, at least two locking legs (5) each connected to said peripheral border (15) via a one piece hinge (18) whose the articulation axis extends parallel or substantially parallel to said peripheral border (15), said locking legs (5) each comprising at least a locking part (19) suitable to cooperate in a removable way with an outer structure (13, 36), called “complementary locking structure”, arranged at the side of the upper border (7) of said body container (3), during a swivelling operation of said locking leg (5) in a “locked” position, the corresponding cooperation involving, simultaneously, a bringing nearer between said peripheral border (15) of lid (4) and said upper edge (10) of container (2), to obtain the crushing of said seal (16).
 2. Packaging according to claim 1, wherein the upper face of the locking part (19) of locking leg (5) and the lower face of the complementary locking structure (13) of container (2) have complementary or substantially complementary surfaces in curved general shape, suitable to cooperate one with the other during the swivelling operation of the locking legs (5) in locked position.
 3. Packaging according to claim 1, wherein the upper edge (10) of the container (2) consists in a roll, projecting towards outside, the complementary locking structure of container (2) being formed by the lower part (13) of said rolled edge (10).
 4. Packaging according to claim 3, wherein the rolled edge (10) comprises, successively, from the upper border (7) of the associated side wall (6), at least the following parts: an upper part (11) in shape of a roll having a general U section, open towards the lower border of the associated side wall (6), suitable to be capped by the peripheral border (15) of the lid (4), and a lower part (13) in shape of a roll whose lower surface presents a section arranged in the general shape of half-circle or half-oval, forming the complementary locking structure and suitable to cooperate with the upper face of the locking part (19) of the lid (4).
 5. Packaging according to claim 1, wherein the side wall (6) of the body of container (3) comprises, at the side of its upper border (7), a moulding (35) projecting towards the outside and whose the lower part (13) is shaped to constitute the complementary locking structure of the container (2), suitable to cooperate with the locking part (19) of the lid (4).
 6. Packaging according to claim 1, wherein some at least of the locking legs (5) comprise a one piece lengthening (20) forming a kind of handle facilitating, for an user, the swivelling operation of said locking legs (5).
 7. Packaging according to claim 6, wherein the one piece lengthening (20) of the locking legs (5) comprises a principal part (20 a), located at the side of the locking part (19), continued by an end part (20 b), by the intermediary of a one piece folding line (22), said end part (20 b) comprising, on the one hand, an opening (28) shaped to allow the passage of the fingers of an user and its gripping, in particular to allow its swivelling compared to said principal part (20 a), and on the other hand, a one piece extension (24) extending in direction of the peripheral border (15) of the lid (4), suitable to come resting on the outside face in opposite of the side wall (6) of the container (2) during the swivelling operation of said end part (20 b), this particularly to form a kind of lever and so as to facilitate the swivelling of the locking leg (5) from its locked position up to its unlocked position.
 8. Packaging according to claim 7, wherein, before its first opening, the principal part (20 a) and the extension (24) forming lever of the end part (20 b) of the locking legs lengthening (20) are also bound together via connections means (26) which are degradable in an irreversible way, for example of the pre-cut line(s) type or of the junction point(s) type, suitable to be broken during the swivelling operation of said end part (20 b) compared to said principal part (20 a), this to constitute witness of opening or tamper evident closure.
 9. Packaging according to claim 7, wherein the one piece extension (24) comprises, at the side of its lower face, a projecting structure (25) suitable to reinforce this extension and to constitute the leaning part for the unlocking operation.
 10. Packaging according to claim 7, wherein the folding line (22) extends transversely over the width of the one piece lengthening (20) of the locking legs (5), and wherein the end part (20 b) of said lengthening (20) comprises: the opening (28) for the passage of the fingers, arranged at the side of the free external edge (27) of said one piece lengthening (20), opposed to the articulation hinge (18) of said locking leg (5), a transversal wall (33), arranged to form a stop aiming at limiting the possibility of introduction of the fingers into said opening (28), and the extension (24) forming lever, extending in the space of the principal part (20 a), on a portion of its length and in direction of said articulation hinge (18) of the corresponding locking leg (5).
 11. Packaging according to claim 2, wherein the upper edge (10) of the container (2) consists in a roll, projecting towards outside, the complementary locking structure of container (2) being formed by the lower part (13) of said rolled edge (10).
 12. Packaging according to claim 11, wherein the rolled edge (10) comprises, successively, from the upper border (7) of the associated side wall (6), at least the following parts: an upper part (11) in shape of a roll having a general U section, open towards the lower border of the associated side wall (6), suitable to be capped by the peripheral border (15) of the lid (4), and a lower part (13) in shape of a roll whose lower surface presents a section arranged in the general shape of half-circle or half-oval, forming the complementary locking structure and suitable to cooperate with the upper face of the locking part (19) of the lid (4).
 13. Packaging according to claim 2, wherein the side wall (6) of the body of container (3) comprises, at the side of its upper border (7), a moulding (35) projecting towards the outside and whose the lower part (13) is shaped to constitute the complementary locking structure of the container (2), suitable to cooperate with the locking part (19) of the lid (4).
 14. Packaging according to claim 2, wherein some at least of the locking legs (5) comprise a one piece lengthening (20) forming a kind of handle facilitating, for an user, the swivelling operation of said locking legs (5).
 15. Packaging according to claim 8, wherein the one piece extension (24) comprises, at the side of its lower face, a projecting structure (25) suitable to reinforce this extension and to constitute the leaning part for the unlocking operation.
 16. Packaging according to claim 8, wherein the folding line (22) extends transversely over the width of the one piece lengthening (20) of the locking legs (5), and wherein the end part (20 b) of said lengthening (20) comprises: the opening (28) for the passage of the fingers, arranged at the side of the free external edge (27) of said one piece lengthening (20), opposed to the articulation hinge (18) of said locking leg (5), a transversal wall (33), arranged to form a stop aiming at limiting the possibility of introduction of the fingers into said opening (28), and the extension (24) forming lever, extending in the space of the principal part (20 a), on a portion of its length and in direction of said articulation hinge (18) of the corresponding locking leg (5).
 17. Packaging according to claim 9, wherein the folding line (22) extends transversely over the width of the one piece lengthening (20) of the locking legs (5), and wherein the end part (20 b) of said lengthening (20) comprises: the opening (28) for the passage of the fingers, arranged at the side of the free external edge (27) of said one piece lengthening (20), opposed to the articulation hinge (18) of said locking leg (5), a transversal wall (33), arranged to form a stop aiming at limiting the possibility of introduction of the fingers into said opening (28), and the extension (24) forming lever, extending in the space of the principal part (20 a), on a portion of its length and in direction of said articulation hinge (18) of the corresponding locking leg (5). 